To monitor the development and control of biofilms formed by Pseudomonas aeruginosa, stainless steel disks were exposed to spectrophotometrically calibrated inocula in growth chambers containing nutrient broth. The chambers were incubated at 37o C and 135 rpm in an orbital shaker. Following a 24 hour period for biofilm development, duplicate disks were rinsed to remove planktonic organisms then scraped to remove sessile organisms. The fluids surrounding the disks and the scrapings from the disks were serially diluted and spread plated for quantification. A second set of duplicate disks was rinsed, exposed to varying concentrations of phenol (0.5 to 5.0% by weight) for 15 minutes, rinsed again, and scraped. Samples from the surrounding fluids were also exposed to varying concentrations of phenol (0.5 to 5.0% by weight) for 15 minutes. As previously done, the fluids surrounding the disks and the scrapings from the disks were serially diluted and spread plated for quantification. Staphylococcus aureus was consistently retrieved from the untreated fluid samples indicating supportive growth conditions. The counts of sessile organisms retrieved from the untreated disks were indicative of supportive growth conditions and indicative organisms' abilities to form biofilms. The counts of planktonic organisms exposed to phenol indicted all concentrations of phenol above 0.5% by weight were able to reduce bacterial populations by 99.99%. The counts of sessile organisms indicated concentrations above 3.0% by weight were able to reduce bacterial populations by 99.99%; the results indicated that significant increases in concentration of phenol are required to control organisms protected by biofilms.